@property --font {
  syntax: "<length>";
  initial-value: 1px;
  inherits: false;
}

:root {
  font-size: max(12px, min(12px + (100vw - 32px) / 55 * 4, 20px));
}

body::after {
  --font: 1rem;
  --px-font: tan(atan2(var(--font), 1px));
  counter-reset: font var(--px-font);
  content: "当前根字号：" counter(font) "px";
}
